CMP Seminars

Title:  Forces that drive the formation of self-assembled nanostructures

Speaker: Xie Chen, California Institute of Technology

Location: Room 1206, Physics Building

Time: 10:00-11:00, Tue, July 21, 2015

Abstract:

In  2D topological phases with symmetry, the fractional excitations in the  system can transform under symmetry in a fractional way, e.g. by  carrying fractional symmetry charges. With different types of  topological order and different symmetries, what symmetry  fractionalization (SF) patterns are possible in general? This question  becomes particularly interesting with recent experimental progress  towards realizing spin liquids and we try to answer this question in  this talk. In particular, we point out that some seemingly consistent SF  patterns are actually anomalous, i.e. they cannot be realized in purely  2D systems. To exclude these cases, we discuss two anomaly detection  methods: the flux fusion method, which is physically intuitive but  applies only to special cases, and the gauging obstruction method, which  is mathematically complete and straight-forward to apply. We give  specific examples of anomalous SF patterns to be detected by these  methods and discuss the interesting possibility of realizing them on the  surface of 3D systems.

Biography:

Professor Xie Chen  received her Bachelor of Science’s degree from Tsinghua University in  physics in 2006. She was a graduate student at Massachusetts Institute  of Technology, working with Professors Isaac Chuang and Xiao-Gang Wen.  She received her Ph.D. degree in 2012 and went to University of  California at Berkeley as a Miller fellow. Professor Chen joined  California Institute of Technology in 2014 as a tenure track assistant  professor. Her work focuses on strongly interacting topological phases,  taking a quantum information perspective, especially the entanglement  perspective, in studying such systems.